MTV talked to Phil Tippett, Eclipse's visual effects master, and he revealed five secrets about the werewolves:

The Wolves Have New Fur, Eyes and Behavior
Weitz requested wolves that had more of a rangy look to them, with matted fur and eyes that more closely resembled human eyes than wolf ones. By contrast, Slade wanted his wolves just a bit more, well, coifed.

"They weren't supposed to look like poodles, but [Slade] wanted them a lot sleeker looking and with shinier, shimmering coats," Tippett explained.

Slade was also adamant that the "Eclipse" wolves revert to the wolf eyes you might see in nature. But it wasn't just the wolf pack's physical attributes that got a makeover for the third installment. Tippett and his team were also directed to adjust the wolves' overall behavior.

"The 'New Moon' wolves, we played them as heroic sentries," said Tippett. "When the wolves met the humans, we attempted to make it appear as though the wolves had a center of conscience that was definitely human. And David really wanted to play it that the wolves were far more primordial and much more wolflike. The wolves became less sentries sent from God and a lot more twitchy, uncertain, fairer animals."

Perhaps the biggest similarity between both films' wolves, however, is that neither set actually has genitals — a compromise necessary to secure a PG-13 rating. "We just deal with it by putting extra fur down there," he laughed.